Airplane laboratory



Aug. 23, 1928. 1,682,138

- A. A. MERRILL AXRPLANE LABORATORY Filed March 25, 1925 Sheets-Sheet l L k l fifa/Weg'.

Augm 28, 19223a ,682,38

A. A. MERRELL AIRPLANE LABORATORY Filed March 25, 1925 :s sheets-Sheet 5 Patented Aug. 28,

UNITED STATES ALBERT A. MERRILL, '0F PASADENA, CALIFORNIA.

AIRPLANE LABORATORY.

' Application led March 25, 1925. Serial No. 18,254.

This invention relates to apparatus adapted for-use in connection with various phases of research work in thel airplane eld, the testing of airplanes prior to being put in service, the training of pilots and recreational pursuits.

The apparatus embodying my invention.

' may be-generally described as an overhead supporting structure from which a full size -airplane may be suspended, means for creating an air blast, and means for directing the air blast against the Wings of the suspended airplane so as to simulate actual flying conditions without the attendant danger.

First consider the adaptability of the apparatus to research work.' Heretoforepractically all research work has been carried on by the use of miniature models suspended in wind tunnels. One of the chief faults of the wind tunnel system resides in the fact that it is impracticable, if not impossible, to reproduce in miniature all structural features of a full size airplane. For instance, the wire bracing system, with its particular degree of resistanpe, is practically impossible of reproduction in accurate proportion. Nor can the true proportion of parasite resistance and conditions of mutual interference be present. With these and other important factors undetermined in a truly accurate sense, it is impossible to predetermine the stability and performance of the actual plane built, as

nearly as possible, after the miniature. On

the other hand, the actual plane is used in connection With my apparatus, giving visual evidence of the performance to be expected of it when subjected to actual flying conditions. Then it is rendered easy, by the use of 'suitable instruments and attachments, to secui'e a recordof performance under known and recorded conditions, from which various desirable computations may be made. The relative efficiency of various motors and propellers can also be determined with exact nicety.

The apparatus is suchthat the actions ofltlie air, the testing activities of the airplane industry have been fraught Withdanger.

That this danger is entirely done away with by use of my apparatus is self-evident.

As a means for training pilots, the apparatus is most useful. In perfect safety a novice may fly the captive plane, and dueto the knowledge of this safety and the consequent lessening of nervous strain, the student can be taught to ily in minimum time and at minimum expense. By imposing upon the plane conditions which call for rectification of the control system, the quickness of the operators response may be noted, and should his reaction be slower than permissible to flood flying, further training must be given the operator; his failure, in the first instance,

having none ofthe disastrous results which if an would have attended a like failure actual flight were being made.

The apparatus is also useful in the amusement field, for pleasure seekers are thereby enabled to enjoy the thrills of flight and piloting Without exposing themselves to danger.

Other novel features and objects of the invention will be made apparent in the following detailed description, reference being made to the accompanying drawings, in which: p

Fig. l is a side elevation of an apparatus embodying my invention and showing an airplane under test conditions Within the apparatus, the air blast director being shown in section;

Fig. 2 lis a View of the air blast director as viewed from the position of line 2-2 0f Fig. l; i Fig. 3 is an enlarged, Vfragmentary view of the air blast director as viewed from the opposite side;

Fig. 4 is an end elevation of Fig. 3;

Fig. 5 is a section on line 5 5 of Fig. 3;

Fig. 6 is `an enlarged, fragmentary section on line 6 6 of Fig. 4;

Fig. 7 is a section on line 7 7 of Fig. 6;

Fig. 8 is a fragmentary section on line 8-8 of Fig. 3;

Fig. 9 is an enlarged fragmentary section on line 9-9 of Fig. 4; y

Fig. 10 is a view similar to Fig. 1 but showing a take-off and landing platform as a part of the apparatus and showing a propeller on the airplane in place of the drag line connecas limitative.

I will first describe the structure whereby the plane to be tested or studied is suspended between periods of simulated flight. An overhead rail 10 is supported at one end by tower 11 while the other end is carried on top upright rail 12. A carriage 13 is adapted to roll along rail 10, there preferably being a cable and pulley system 14, adapted to be operated from the ground, whereby the carriage may be shifted along the rail. From carriage 13 depends a suspension cable 15 adapted for attachment to the airplane to be tested.

In Fig. l bi-plane 16 is shown to be propeller-less, the nose of the plane being connected by cable 17 to spring balance 18 which, in turn, is secured to carriage 19. Carriage 19 is adapted to roll up or down rail 12 and may be positively rolled or controlled by means of cable and pulley system 20.

At the vother side -of rail 12 is provided an air blast directing member 21, which may be generally described as a honeycomb structure, wherein the ends of the cells are open to provide through passages for the air blast, and in which the cell defining walls are movable so air currents passed therethrough may be varied in direction.

I have shown the honeycomb structure within a supporting frame made up of ends 22, top rail 23, base 24 and a central upright or partition 25, of which rail 12 may be a part. A typical cell is defined by side walls 26 and top and bottom walls 27; the top and bottom walls being pivotally mounted at one end so they may be swung angularly through a vertical plane, and the side walls being pivotally -mounted so they may be swung through horizontal planes. Now it is not necessary to the invention, considered in its broader aspects, to so mount the walls or vanes, nor is any particular method of controlling the vane movement essential to the invention. For the purpose of illustration, I have shown structure 21 divided into units of several cells each, with means for moving the vanes of each unit simultaneously. However, it lies within the scope of the invention to provide means for moving each vane independently. When employing the unit system of control it is preferable that upright 12 be at a dividing line between units so the delivered air blast' may be divided at the nose of the tested airplane.

In Fig. 3 I have shown a typical example of unit control. The horizontal vanes 27a are mounted on rock shafts 28 which are journaled at one end 29 on upright 25, while the other ends of the shafts extend through and beyond sleeves 30 on which are mounted horizontal vanes 27",. Sleeves 30 are journaled at 31 on uprights 22 and 32. On shafts 28 are crank arms 33, interconnected by links 34, and one of the arms is attached to control rod 35 which extends downwardly into connection with operating handle 36, the latter being connected to a toothed wheel 37 journaled on stationary stud 38. It is evident how radial movement of handle 36 imparts like movement to vanes 27a. There may be a locking pawl 39 adapted to hold wheel 37 and hence handle 36 and vanes 27a in adjusted position.

A similarl control system is connected to sleeves 30 whereby they may be rocked t0 adjust vanes 27b independently of vanes 27a.

Vertical vanes 26d are mounted on verticallyextending shafts 40 which are supported in bearings 41 at the top and extend downwardly through hollow shafts 42, the latter being journaled on base 24 at 43 and carrying vanes 26". The ends of the sleeves carry cranks 44 which are interconnected by links 45, whereby the cranks may be moved to swing vanes 26b simultaneously by swinging operating handle 46, the latter being connected to the crank and link system by rod 47.

The lower ends of shafts 40 extend below sleeves 42 at 48, there being provided a crank and link system 49, similar to that described in connection with sleeves 42, and operable by handle 45, for swinging vanes 26a independently of vanes 2Gb.

Mounted behind member 21 are the propellers 51, preferably independently driven and controllable, which are adapted to deliver air blasts through the cellular strueture. The propellers may be provided in any desired number and arranged and supported in any suitable manner. I have illustrated them being supported on framework 52.

Referring to Fig. 1, I will now describe -one method of using the apparatus to advantage. IVith airplane 16 out of the field of action, propellers 51 arevstarted up and independently adjusted as to speed, and the direct-ing vanes are adjusted, until tests show that the air blast is uniform throughout, as measured through the vertical field in front of member 21. This may involve the partial or entire blocking off of certain cells, as, for instance, by plates -53 (Fig. 2).

Air plane 16 is then suspended by cable 15 and connected to balance 18 by cable 17. Propellers 51 are then sped up, and the airplane elevator and ailerons adjusted until the plane starts to lift, slackening cable 15; carriage 19 being rolled upwardly in order to lll() neeaiss maintain cable l? as nearly horizontal as pos sible. A reading et balance l@ gives the drag ot the airplane, which is equivalent in amount to the necessary thrust olz the screw were the airplane moving through the air in place ot the air moving past the captive plane, while a reading of anemometer 5d on the plane gives the air speed.. it most convenient and useul record may be made by a. series ot photou graphs or' the apparatus and plane as the plane or its controls are changed in position. For instance, there may be a datum line established by a cross bar 55 (or the datum line may be in the torni ot a cross hair in the camera used). Suppose a photograph were talren when the plane `flies steadily. lt will. show the air speed, as indicated by anemometer 5l; the drag, as indicated by balance 18 the anffle ot incidence b reason of the y i 7 :n i y photographed datum line; 'the elevator ann gle; and other useful information. llfith the weight of the machine known, it will be seen that comprehensive graphs may be drawn and various helpful computations made from which the performance muy be ligured. Heretol'oie, so tar as l have been aware, it has been impossible to secure such information from full size machines with any considerable degree ot' accuracy, similar intoin'iation gained from small models does not always hold true for ull size machines.

lll/'here the machine is to be 'tested or the pilot trained in tlying, the air speed may be varied or the director vanos shifted to simulate practically any condition which may be encountered in actual dying. 'lhis will be apparent 'from the foregoing and need not be further discussed.

ln making certain tests and in training' pilots, it is 'desirable that airplane propeller lP be used for holding the plane in equililon riuni, (Fig. l0), rather than drag line 17.

this way, knowing the air speed and noting,r the airplane propeller-ls angular velocity, it is possible to determine the relative efliciency ot iiopellers having dillerent cliarad teristics. Thefphotographie method ot recordation may be used, the pilot communicating with the observer by means of telephone line T, and advising him of the motors l. P..

at the instanttlie picture is taken.

ln training pilots, it is `desirable that a vertically adjustable take-oli" and landing platform 56 be used. For instance, this plattorni may be mounted on collapsible V-frames 57, which are adapted to be spread or closed by means of aright and left llead-screw 58 operated by motor 59. By telephonie communication, the trainer, who controls the air speed and director vanes from the ground, and the pilot may he kept mutually advised. asto engine and air speed, and act accordingly. For instance, suppose the plane to be in flight and it is desired to simulate a landing. The trainer gradually decreases the air speed, advising the pilot constantly-'oil the instant air speed. The pilot manipulates his controls and ydecreases his engine speed accordingly, and it the plane settles properly the landing platform. is raised .to meet the plane, and the landing is made. @n the other hand it it is evident to the trainer by observation that tlieairplane is not trimmed -for a good landing the platform is kept away from the plane and any shock due to lach oit con trol is taken by the shock absorber loa interposed between the plane and the support= ing member l0.. i

@t course it lies-within the scope ot my invention to substitute tor the rigid beamlo a steel cable properly anchored which will itself give a sucient resiliency to care tor all shoelrs. 'lhe pilot, ,oil course, must endeavor to malte a gentle landing without let-- ting the plane move appreciably towards or away from director 2l,

'llie various training exercises possible through use or the' apparatus are many, the plane may be exposed to practically any condition to be met in actual dying, as will be apparent to those skilled in the art.

ln liig. ll, suspension rail l0 is shown as inclining downwardly towards director 22a, lthe latter being disposed-in a plane pei'pend e ular to rail l0, so the normal air blast may be directed parallel to the normal line et travel of glider 16a when it is allowed to gravitate., 'llhis type of apparatus is espe,- cially useful in the practice oit soaring on an upward wind.. p

lt is believed a full understanding ol-l the invention will he had :trom the foregoing, but it will be understood the drawings and description are merely illustrative ot' and not restrictive on the broader claims appended hereto, for various changes in design, structure and arrangement may be made without departing from the spirit and scope ot said claims.

l claim:

' 1. ln apparatus ot the character described, the combination or" an elongated overhead support, a carriage movable over the support longitudinally, a cable suspended from the carriage and adapted for attachment to an airplane, means for delivering an airblast, and means adapted to direct the air blast beneath said support towards the airplane.

2. In apparatus of the characterdescribed, the combination ot an overhead support, a cable suspended from the support and adapted for attachment to anairplane, means for delivering an air blast, andangularly adjustable vanes adapted to direct the air blast beneath said support towards the airplane.

3. In apparatus of the character described, the combination of an overhead supporp, a cable suspended from thesupport and radapted for attachment to an airplane, means adapted to direct an air blast beneath the supdll lll@

port towards the airplane, an upright arranged forwardly of the suspension cable, a carriage substantially vertically movable along the upright, and a drag line anchored at one end to the carriage and adapted for attachment at its other end to the forward end of the airplane.

4. In apparatus ot the character described, the combination of an overhead support, a cable suspended from the support and adapted for attachment to an airplane, means adapted to direct an air blast beneath the support towards the airplane, an upright arranged lforwardly et' the suspension cable.I a

`carriage substantially vertically mo 'able along the upright, a dragI line anchored at one end to the carriage and adapted for attachment at its other end to the forward end ot' the airplane, and manually operated means adapted to move said carriage in the manner specified.

5. In apparatus of the character described the combination of an overhead (support, cable suspended from the support and adapted for attachment to an airplane, means for delivering an air blast, and means adapted to direct the air blast beneath said support to- Wards the airplane, said directing means embodying movably mounted vanes interposed betweenthe suspension cable and air blast delivery means.

6. In apparatus of the character described, the combination of an overhead support, a cable suspended from the support and adapted for attachment to an airplane,` means for delivering an air blast, and means adapted to direct the air blast beneath said support towards the airplane, said directing means embodying movably mounted vanes interposed between the suspension cable and air blast delivery means; and manually operated means adapted to move said vanes selectively.

7. In apparatus oli' the character described, the combination of an overhead support, a cable suspended from the'support and adapted for attachment to an airplane, means for delivering an air blast, and means adapted to direct the airblast beneath said support towards the airplane, said means embodying a honey comb structure interposed between the suspension cable and air blast delivery means', the horizontal defining Walls of the honeycomb cells being pivotally mounted on horizontal axes which are substantially at right angles to the axes of the cells. l

8. In apparatus of the character described, the combination of an overhead support, a cable suspended from the support and adapted for attachment to an airplane, means for delivering an air blast, and means adapted to direct the air blast beneath said support to.

Wards the airplane, said means embodyinging a honey comb structure interposed between the suspension cable and air blast delivery means, the horizontal defining walls of the honeycomb cells being pivotally mounted on horizontal axeswhich are substantially at right angles to the axes o'f the cells; and means adapted to move said horizontal Walls selectively about said horizontal axes.

9. In apparatus of the character described, the combination ot' an overhead support, a cable suspended from the support and adapted 't'or attachment to an airplane, means for delivering an air blast, and means adapted to drect the air blast beneath said support towards the airplane, said means embodying a` honeycomb structure interposed between the suspension cable and air blast delivery means, the vertical defining walls of the honeycomb structure being pivotally mounted on vertical axes.

l0. In apparatus ot' the character described, the combination ot an overhead support, a cable suspended from the support and Aadapted for attachment to an airplane, means for delivering an'air blast, and means adapted to direct the air blast beneath said support 'towards the airplane, said means embodying a honeycon'i-b structure interposed between the suspension cable and air blast delivery means, the vertical defining walls of the honeycomb structure being pivotally mounted on vertical axes, and means adapted to move said vertical walls about said vertical axes.

In Witness that I claim the foregoing I have hereunto subscribed my name this 13th day ot March, 1925.

.ALBERT A. MERRILL. 

